Circular loom



June 24, 1952 v. M. J. ANCET 2,601,358

CIRCULAR LOOM Original Filed Dec. 27, 1948 4 Sheets-Sheet l INVENTOR June 24, 1952 v. M. J. ANCET 2,501,353

CIRCULAR LOOM Original\Filed Dec. 27, 1948 4 Sheets-Sheet 2 INVENTOR A a 3 i 3 M m c 1 m mm m w au 2 a M m r H W" a UM cm NL m w m V.C

June 24, 1952 Original Filed Dec. 27, 1948 Patented June 24, 1952 UNITED STATES PATENT OFFICE Divided and this application May 3, 1950, Serial No. 166,041. In France April SCI-aims.

This invention relates to circular looms, which produce fabric in tubular form by means of a shuttle moved along a circular path within a shed made of sheets of warp threads. In such looms, the driving means for the shuttle necessarily lie outside the shed and, accordingly, act on the shuttle through one sheet of threads of the shed. Heretofore, the shuttle and driving means have been connected by mechanical means or else the shuttle has been made of magnetic material and held in place relative to the driving means, so as to be propelled thereby, by magnetic attraction. In prior circular looms, in which the shuttle and its driving means are connected mechanically, the warp threads in the sheet of the shed, through which the cooperating parts of the connection act, are subjected to abrasion, which is liable to do damage to the threads, particularly if they are of fine size. Also, in prior looms, in which the shuttles are driven either mechanically or magnetically, the shuttles are of complicated construction, so that they are expensive to produce and difficult to insert into and remove from the shed. The present invention is directed to the provision of a novel circular loom, which includes, among other features, a new shuttle assembly and driving means therefor, the assembly comprising a shuttle and a frame, in which the shuttle is mounted and which includes a leading portion or nose preceding the shuttle and facilitating its movement through the shed and a trailing portion for guiding the weft thread issuing from the shuttle. The shuttle is formed at least in part of magnetic material, is hollow and has an external shape, which is that of a surface of revolution and is preferably generally cylindrical, and is supported with its axis extending toward the fell of the fabric in the same general direction as the warp threads in the shed. The weft thread package is carried within the interior of the shuttle and the thread is led through an axial opening in the top of the shuttle and through a guide eye in the trailing portion of the guide frame. The driving means for the shuttle assembly are mounted to rotate about .the axis of the loom and include a plurality of positively driven and, as a result, the shuttle 2 is caused to rotate on its axis and thus rolls over the warp threads in the sheet of threads referred to.

In addition to the new features mentioned, the new loom includes novel means operating, in the event that the shuttle assembly encounters an obstruction in the shed, to free the assembly from its driving means, shut down the loom motor or other drive means, and apply a brake to stop rotation of the shuttle assembly drive means quickly.

This application is a division of my application Serial No. 67,341 filed December 2'7, 1948.

For a better understanding of the invention, reference may be had to the accompanying drawings, in which Fig. l is a view, partly in side elevation and partly in vertical section, of a shuttle assembly used in the loom of the invention;

Fig. 2 is a diagrammatic perspective view showing the mode of operation of the shuttle assembly of Fig. 1;

Fig. 3 is a view in side elevation showing the shuttle assembly carrier of the loom;

Fig. 4 is a sectional view on the line 44 of Fig. 3;

Figs. 5 and 6 are plan views of the carrier and shuttle assembly showing, respectively, the normal position of the assembly and the deflection of the frame of the assembly, when it encounters an obstruction in the shed, and the dislodgment of the assembly from the carrier.

Fig. '7 is a fragmentary vertical sectional view through a modified form of shuttle assembly; and

Fig. 8 is a view of the modified form of shuttle assembly in side elevation.

The new circular loom comprises a central vertical shaft H), which lies within a cylinder of warp threads I l supplied from a pair of beams and passed upwardly through a reed l2. Below the fell of the finished fabric 13, the warp threads are separated by suitable heddle mechanism into inner and outer sheets l3a, [3b, defining a shed I4 within which operates a shuttle assembly l5.

The shuttle employed in the new loom is hollow and has an external shape, which is that of a surface of revolution. The shuttle has a central zone of magnetic material and is preferably made of such material throughout. The shuttle comprises a hollow body l8, illustrated as being of cylindrical form, and closed at one end by an integral closure plate l9, which is provided with a central pivot 26 on its outer face and with a spindle 2|, which extends coaxially within the body. Preferably, the central zone 4 Ma of the body is of heavier wall thickness than ends and spindle 4% projects through its lower the ends and the thickened zone is defined at its roller 58 and carries another roller 49, which is ends by circumferential shoulders 22. The upper connected by a belt 59 to a pulley loose on end of the body is closed by a removable cap 23 shaft ill and held stationary by appropriate of generally conical form threaded into the end 5 means. Accordingly, as the shaft rotates and of the body. At its upper end, the cap is formed swings the carrier with it, roller 353 is rotated by with a hollow boss 26, near the lower end of the belt and rotates its spindle GB and the rollers which there is a circumferential shoulder 25. "d smounted fast thereon. When the shuttle is in use, it contains a bobbin In the operation of the loom, the shuttle as- 26, which is mounted on the spindle to rest on '10 "sembly is placed in position with the shuttle beara circumferential enlargement 2 la at the lower ing against rollers 48 on spindles d5, 4? of the carend thereof and slightly above the inner face rier, the brackets 43, 4 3 being so adjusted that of closure [9. A supply of weftthread 21 is "the surface of the shuttle lies close to but spaced wound on the bobbin. A frustoconical sleeveZB from the outer ends of the core of the electrolined with felt or like material may be placed'to- 1'5 magnet. The energization of the electromagnet rest upon the thread wound upon the bobbin causes it to attract and hold the shuttle in poto act as a brake. The weft thread from the bobsition, so I that it is advanced with the carrier, bin passes upwardly through the opening in the and the increased wall thickness of the central hollow boss 24. "zone Eda of the shuttle increases the attractive The frame, which forms part of the shuttle aseffect. The distance lengthwise of the shuttle be- Sembly inthe constructionillustrated in Figgl, tweenshoulders"Zi-thereon is 'slightly'less-than 'eempnsesabase 29,"which-may 'be'a straight 'the distance betw'en 'the opposed faces *of the length of wire having a loop at one end, within -"rollers on spindles ififdl, ahd,-'-when-"the'-shuttle -whi ch-is--1nountedan annularbearing disc illl. assemblyis-placed-hrpositionfthethickened-zone The shuttle iests on thedisc :wi th itspivot 2B 25 8a of -the s'huttle l-ies between the upper and entering the-openingthrough-thedisc. The base lower'pairs 'of rollers. The-assembly is then-pre- 29 iitn ds" forwardly from the shuttle a subvented-'frbm droppingdownwardly by engagement 1staitial-dist anco-and apair-of elements-3i, which ofthe lower-shoulder 22 'with the tops "of the *m ay be wires; extend-upwardlyfand rearwardly rollers 'ofthe lower pairand the-shuttleassembly from the forward end of the baseand over the 30 'is; advanced without bing supportedon the reed. top of the shuttle. For convenience, the elements A shaft 52 ni'o 'ted imbracKetS eS, ri l-is en- '3lmay bear continuous length-of wire, which is "circled by a spring- 53 connected '-to bracket it formed with a loop -the bight of which lies above and the sh t andacting to 5 swing" the shaft the-' fsh uttle' and carries an-annular bearing disc --'counte'r1ee- 1se,-u'/hen"it-is viewed from thetop.

"32. 'Ihedisc rests upon the shoulder 25 at the Between "its-ends}'the' shaft carries-a lever"-'54, top of the cap of the shuttle and the hollow boss on-which a s'mall' roller 55*is' mo'unt'ecl'at'oneiend. 24'- extendsthrough the openingin the disc. A The other-"end of-the lever is cohnectedbya rod plate 33 ismounted for swinging'movement on a 55 to an E'ien a shaft ES mGun'ted on an arm crossbar 34 extending between-the elements-3! "ESfast on shaft If]. The shaft carries a'pa'wl 'fib, "anda-t'rolley 35 extends upwardly and rearward- "which' may be swung'byrocking of-Shaft 58 into 1y fr'orn'the'plate and is provided witha weft contact 'witl1 teetl1 on the ner face-"of a fi'at thread guide 36 at its free end. A spring 3? is ring" 6l,='whi'ch -lies between per-and'-'-lowerfricconnected atone-end to the plate and'at the -tion rings S'Zheldstationa'ryand pressd against other end to a'wire' 33, 'which'is connectedto the ring 6| by suitable 'ine'ans. Shaft 58 also carries 'base 29. The'spr'ing tends to'hold plate 33 with "a"contact blade' E53, wmchg'upen swinging of the the trolley 34 in erect position, as shown in" Fig.1, shaft; is 'rnovedbe'twe'err 'sprihg cofitaict members and counterclockwise swingingmovement of' the 64 ablock of insulation"fi'fld'shitablysupported trolley is'permitted but-is resisted by the spring. 'so' astoi'no've withshaft it. :whecemacvmem- 'When' the shuttle is to bein'serted in or removed bers' 'a're -in a circuit which, when established by fr'oni the frame, the base Ziland members 3! are ir'1sertion of blade 63 between 'them; ol erates'com sprung apart'sufficiently to-f'ree disctil onthe 'venti'o'nall'o'om stoppi'ng m'eans. -Norinally,-\vlien base from pivot pin 8" ontheshuttle, after-which the' 'shuttle assembly" is in place on the carrier the-shuttle maybe -rnoved endwise to withdraw "with the shuale engagmg'rende -as;the surface boss 24 from disc 32. of the shuttle be s against rbllez and-forces The shuttle assembly is moved by a carrier in d? backwardlyj that -sha'ft fis is =l'i'eldina poa circular path through a shed of Warp threads, 'sitiorl with its pawl efl' fl ee of theteeth of rii-lg which is opened ahead of the assembly and closed 61' and'contact blade- 63 61113 ofcontact-'- with the behind it by the heddlemeohanism. The carrier spring termmarmembents. 1fthe-shuttled comprises a sleeve 33* fast on the shaft and prosembly 'is displac'ed f' om 'the'carrier; the shaft vided with upper and lower; radial arms 40,- be- 52 is-=swung byfits spring ands 'ng's' shaft 58;so tween v'ghioh is mounted an electromagnet 4| "thatthe paWI t engages th-tthbf'Tihg 6| fhavinga- U-shaped core :22. The legs of the core a and the-'circuit througli' the lo'd stopping means *exte'nd 'radially outward beyond the-ends of arms is closedby insertion of bladet,between-termi- 40 andlie one above the other, their outer faces -nal 'members- 64. v "The 'engagement of the pawl bein 'concave. A pairfof bracketsWi-M- are 65 with ringl5I causes-thacarrierand loom shaft "mountedon the upper andlowersurfaces of arms to be braked; so that the niovingparts of the loom 40,-the brackets being'longitudinally slotted and "will piempuy cemetossto p heldin place by screws 15 passing through the Wherf'the'shuttleassembly is in operating posislots; so'that'the brackets may be moved to differti'on in theshed, the 'long itudinaI axis of the 'ent' positions of adjustment lengthwise of arms 7 -shutt1e eitends tdward the fell- 'of the goods- -in '40. Each bracket has extensions projecting the same general direction as the warp threads beyond opposite sides of its arm at and a pair of in the-shed. The base' er mme ll exteiids-forspindles d6, 41 are mountedin corresponding exwardly"f-idni the shuttle ahd th reward-end- 'of tensio'ns on opposite sides of arms 413. -Each itmmaseend-wne ends of elernents 3f connected *spmcn carries rollers neat its-upper and-lower thereto "'fbrm" which leads the shli'ttle in its movement. The trolley 35 extends rearwardly from the shuttle and the weft thread passing through the guide eye 36 lies close to the fell of the goods in position to be beaten up. The shuttle is free to rotate on its longitudinal axis in the frame and the shuttle assembly and the carrier lie on opposite sides of the warp threads in the inner sheet i3a of the shed. During the rotation of the carrier with shaft iii, the rollers 48 on spindle 46 are caused to rotate and this movement is imparted to the shuttle, so that it has a planetary motion, in which it travels along a circular path concentric with the loom shaft [0, and, at the same time, rolls over the threads in the inner sheet of the shed. By making the shuttle in the form of a hollow body, the external shape of which is that of a surface of revolution, the shuttle is of simple construction and it may be readily caused to roll over the warp threads so that abrasion of those threads is avoided.

In the normal operation of the loom, the frame, which is free to pivot on the shuttle, is so held that it leads the shuttle, because of the drag of the inserted weft thread on trolley 35. If a warp thread, such as that designated i la (Fig. 5), becomes broken, for example at the top of the shed, and drops down to become entangled across the other warp threads as though it were a Weft laid by the preceding shuttle at the bottom of the shed, it produces an obstruction in the shed, which is first encountered by the nose Ha of the frame of the shuttle assembly. When such a shed obstruction occurs, it is desirable to have the loom stopped at once and, when the nose of the assembly meets the obstruction, it is forced outwardly thereby and penetrates the warp threads of the outer sheet l3b of the shed. A stationary ring 65 having teeth 650. on its inner surface is mounted outside the shed in such position that, when the nose Ila of the frame of the shuttle assembly is forced outwardly as described, the nose engages one of the teeth on the ring. The shuttle assembly is thereby arrested and, as the carrier continues to move, the assembly is dislodged from the carrier. As soon as the shuttle moves away from rollers 43, shaft 52 is free to be swung by its spring 53 and this results in the stopping of the loom and the braking of the moving parts thereof, as previously explained.

The shuttle assembly, shown in Figs. 7 and 8, comprises a shuttle 85, which includes a body 61, which has the normal external shape of a surface of revolution and is illustrated as being generally cylindrical in form. The body has a central zone of magnetic material and preferably is made throughout of such material and has a central zone 81a of increased Wall thickness. The lower end of the body is closed by a plate 68, formed with a central opening, in which is seated a flanged bushing 59 of non-metallic material, such as impregnated fibrous material. spindle it extends upwardly from the closure within and coaxially of the body, the tubular portion of the bushing extending through the closure plate and into the spindle. The closure plate is formed with a circular row of openings H. The top of the body is closed by a cap 12, which may be frusto-conical form and is constructed to telescope into the open end of the body. The cap has openings 13 in its inclined surface, which lie outwardly from the axis of the body a greater distance than the openings H. The cap is formed with a hollow boss 14, which is encircled by a flanged bushing 15 of. non-metallic material and is held in place by a turned-over bead at the outer end of neck M. The bushing is A tubular I formed with a flange at its lower end, which may be seated in a depression in the top of the cap around neck 14 and preferably has a conical upper bearing surface.

The frame of the shuttle assembly, shown in Figs. 7 and 8, includes a base 16, which may be of sheet metal of channel section and is provided adjacent one end with a pivot pin 11 rising from a fiat disc on top of the base and receivable into the bushing 69 at the lower end of the shuttle. At its other end, the base carries a thin vertical plate 11, to which is pivotally attached an element '18 extending upwardly and rearwardly to overlie the top of the shuttle. The element carries a trolley 19 extending upwardly and rearwardly therefrom and provided at its free end with a weft thread guide 80. The free end of element 18 lies parallel to the base and has a central opening containing a bearing bushing 8|, into which the neck 14 of the shuttle with its bushing 15 may be received. The base 16 and element 18 are connected by releasable means.

which are illustrated as including a wire 82 at tached to the upper end of element 18 and terminating in a loop 83. The base 15 of the frame carries a wire loop 84 interconnected with loop 83, loop 84 being formed with portions 84a, 84b of different height. Wire 82 is formed with a kink 82a, so that its length may be increased by the flattening of the kink. When loop 83 of wire 82 is engaged with the lower part 84a of loop 84, the base and element 78 are held in engagement with the ends of the shuttle. When wire 82 is swung to bring its loop 83 within the higher portion 84b of loop 84, the base and element may be swung apart on their pivotal connection, so that the shuttle may be readily removed from the frame.

The weft thread 83 issuing from the shuttle through the opening in the hollow neck I l passes through tensioning means 86 of conventional construction mounted on the top of element 18.

The shuttle assembly shown in Figs. 7 and 8 is intended to be supported in its movement along its circular path on the reed I2 of the loom and, to facilitate the movement of the assembly along the reed, the base 16 of'the frame may be provided with a roller 8'1, which is mounted on a horizontal pivot 88 lying transverse to the base and in the axis of rotation of the shuttle in the frame. In an alternative construction, the base is provided with a shoe in the form of a fiat disc 89 of non-metallic material, such as impregnated fabric. The disc may be mounted on base 16 by a ball and socket connection lying in the axis of rotation of the shuttle or on a horizontal pin 90, which extends transverse to the base and lies in the axis of shuttle rotation.

The shuttle assembly shown in Figs. '7 and 8 is moved about the axis of the loom in the same manner as the assembly shown in Fig. 1, that is, the assembly is held by magnetic attractionwith the shuttle engaging the rollers 48 at the outer end of the carrier. The frame leads the shuttle in the movement of the assembly and the plate Tl forms a nose which, upon encountering an obstruction in the shed, is forced-outwardly between the threads of the outer sheet of the shed into engagement with the teeth of stop ring 6|. As the assembly is moved along with the carrier. the shuttle rolls on its longitudinal axis and the disposition of the openings H and 13 is such that, in the rotation of the shuttle, a current of air-is caused to pass through the shuttle by centrifugal action. The air current tends to keep the interior of the shuttle free from lint, which otheralongsaid path, a member 1 carried by and :eX- .7

"tending ahead of the shuttle, :themember f being deflected from its normal path upon encoun-tering -an obstruction inthe shed and means-ex- I tending-adj acent the path of travelof the shuttle and engageable by-Ethe member-when -defiected therebyto arrest the shuttle 1 andcause its disengagement from the carrier.

2; In I a circular- 1oom, in=-whioh-warp threads "are separatedinto' spaced sheets' to form ash'ed,

- 'the combination ofabarrier-movable in -a-"-path "about theaX-is of--the* 1oom,:- a; shuttle movable '-th'rough theshed and made at least in -part of magnetic material, the" eXternal-shape'bf the shu'ttle' being that of-a' surface of revolution,-- an electromagn'et on the carrier acting on the shut -tle"to'hold it againstpart-of the carrier with one sheet-of the "shed therebetweenwhereby the shuttle rolls on the" saidsheet *asthe carrier movesalong 'saidpath'; a member carried by-and ."extending ahead of the'shuttle, the member being.

" deflected "from "its normal path upon encountering an obstruction in 'theshed, meansexten'ding adjacent the path of travel of theshuttle' and "enga'geable by the-member when" 'd'efiectedth'erebyto arrest the shuttle and cause" itstdisengage-... ""m'ent'fr'o'm the carrier, and "a'loom stopping meansactuator comprising means; held inoperafive by the shuttle when in place against the carrim and rendered operative upon disengagement of the shuttle from the carrier.

3. In a circular loom, inwhich" warp threads are separated i'ntospaced sheets to form a shed, the combination of a carrier movable in a path about the axis-of the loom,-a shuttle movable through'the shed and made at least in part of,

, magnetic mater-ialf the external shape .of the shuttle being'that of a surface of revolution,-an Telectromagneton the carrier acti'ng'on the shuttle to --hold it K against part ofthe carrier With one sheet of the shed therebetweenwhereby the;

shuttle rolls on the-said sheet as the carrier moves along said-path, :a member oarried'by and -extending ahead -of--theshu-ttle; the member a being 1 deflected "from its normal. path =.-uponen- 'countering an obstruction inthe shed, stationarvt means' extending-adjacent the-'path of travel of the shuttle and engageablebythe member-when deflected thereby toarrest the-shuttle-and cause its disengagement-from-the carrienand a'loom stopping means actuator comprising means held-1w -inoperativeaby the-shuttle 'wheniniplace against the carrier and rendered operative :upon disengagement of theshuttle from :the carrier.

'4. In a circular loom-irrwhich warp threads .:are separated into spaced sheets "to' form ashed, the combination of acarrier movable a pat-h --'about the axis :of 'the"loom,a; shuttle' movable throughthe shed and made at least in'p'art of -magnetic material, an eleetromagnet on the c'arrier V acting on the shuttle to hold 'it against 'p'art ofathe 'carrienas thela'tter moves along saidpath,

'aa'memb'er carried-by:and extendingiahead brothe :shutt1e, the memberbeing? deflected fromitsnorinal path supon encountering an'robstructiontin the shed,i a"curved ltoothedielement :extending adjacent the: path; of travel of thew-shuttle; the :member; upon beingQd'efiected; engaging a' itooth of the-fielement: and: being held the-reby against .furth'en 'forward movement," whereby the shuttle -'-is i disengaged from the carrier, and a .loom: stopiping means actuator comprising means held inoperative I bytthe shuttle-when in place:,against the :tcarri'er :and' rendered :operative upon: disen- Igagement lot "the shuttle from the carrier. r J .5.i.In-"a; circu1ar .loom,a.in:which warpv threads ,aresieparatedinto gspacedsheets to formtawshed, thenc'ombination of: a carriermovable inarpath about; the: axis-"of- .theloom, a'shuttle" movable through the shedwand made at least aim part of magnetic materialyan electromagnet on thez=car- 'rier" acting on the shuttle to :hold it againstpart of the vcarrier as-the latter; moves. along said'path, a -frame mounted on thexshuttle for-swingin movement, :the framerhaving whose-projecting -forwardly= ahead of the shuttle; the saiduframe andpnose being deflected from the normal; path 2 upon encountering an obstructionin; vthe shed, and means extending adjacentv the path ofztravel of t-he- 'shuttle and enga eable by :the nose of the frameiwhen deflected thereby toarrest the shut- :ttle and cause its: disengagement :fromthe carrier. :6. *Inra circularloom, in which: warp threads are separated into"sp'a'ced'sheets to form a shed, the combination of a carrier Y movable in: a path about-the axis of "the loomya shuttle(movable through the shed: and 'ma-deat least -in:part of magnetic material, an: electromagneton-the zcar wrier-acting on the; shuttle to i holdit against-part ofthe carrier asthe latter moves along said path, a --:frame 'mounted on the shuttle nforswinging 0 --m'ovement,- the 'frame :having a nose projecting forwardly ahead of-the=shuttle,-'the-said frame and nose :beingdeflected from the "normal -path upon? encountering anobstructionin the shed, rmeans extending adjacent-the path of itravelof the-shuttle; and engageable by- :the: nose of rthe framerwhen deflected therebywtoarrestthe shut- .tleandcauseits disengagementfrom the carrier, and a :loom' -stopping-means-. actuator comprising means held: inoperative 'by the shuttle when in place against the carrier and rendered-operative zuponw disengagement of a the -shuttle- :from* the carrier.

'7. In a circular loom in which warp-threads areseparated into spaced sheets to form a=- shed, the combination-of a earrienmovable in a/path aboutthe axiaofthedoom; a-shuttle movable through the-:shed and made atlea'st in partrof tm'agneticwmaterial, an electromagnet-ron thecarrier acting on the "shuttle: to hold it against-part -i ofthe' carrier as the latter moves along: said-path, a- :rr'ame' mounted cnx'the shuttle for swinging -movernent;i the frame having a:nose projecting forwardly ahead 01 the. shuttle; the .said frame aand nosel'being deflected from the normal-path 65. upon encountering an; obstruction ."in' the shed, fstationary means's extending" adjacent fthe path of travel ofathe shuttle: and *engageable 'by the nose :of the-frame whenv deflected; thereby to ar- -:resttheshuttle. and cause. its'disen'gagement' from 70 theucarrier,. anda :loom stopping means actuator 'comprisingmeansi heldzinoperative by: the shuttle "when in place'vagainst the carriei -and i'endered "operative npon'disengagement of 'the shuttle from thecarri'er.

' 8. -'In a i'circular 100m; in which L warp threads are separated into spaced sheets to form a shed, the combination of a carrier movable in a path about the axis of the loom, a shuttle movable through the shed and made at least in part of magnetic material, an electromagnet on the carrier acting on the shuttle to hold it against part of the carrier as the latter moves along said path, a frame mounted on the shuttle for swinging movement, the frame having a nose projecting forwardly ahead of the shuttle, the said frame and nose being deflected from the normal path upon encountering an obstruction in the shed, a curved toothed element extending alongside the path of travel of the shuttle, the nose of the frame, upon being deflected, engaging a tooth of the element and being held thereby against further forward movement. whereby the shuttle is disengaged from the carrier, and a loom stopping means actuator comprising means held in- 10 operative by the shuttle when in place against the carrier and rendered operative upon disengagement of the shuttle from the carrier.

VICTOR MARIE JOSEPH ANCET.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 365,216 Winckler et a1. June 21, 1887 1,968,041 Jabouley July 31, 1934 2,027,459 Yeadon Jan. 14, 1936 2,055,604 Jabouley Sept. 29, 1936 FOREIGN PATENTS Number Country Date 606,352 Great Britain Aug. 12, 1948 

